intellectual property and bikes

design patent

The trend in mountain and cyclocross is to drop your extra chainrings and your front derailleur to run a 1x system. The hope is that removing the front derailleur will increase reliability and decrease weight. And, frankly, it looks pretty sharp.

1x drivetrains used to require a chain guide to keep the chain on the chainring. Clutched rear derailleurs, like Shimano’s Shadow Plus and SRAM’s Type 2, keep tension on the chain to decrease chain dropping.

But, the narrow wide chainring is the final piece of the puzzle to reliably keeping the chain on without requiring a chain guide. Narrow wide is pretty descriptive – teeth of the chainring alternate between having a narrow width and a wide width. The wide teeth grip the links of the chain to hold the chain on the chainring.

After SRAM’s introduction of the XX1 mtb drivetrain, several manufacturers introduced their own narrow wides – for example, RaceFace and Wolf Tooth.

On October 21 and October 28, 2014, SRAM was awarded US design patents D715,699 and D716,191, respectively. Both design patents are drawn to narrow wide chainrings.

From D715,699:

From D716,191:

It is important to remember that it is the solid lines in the figures that define the covered, patented subject matter.

With a fast, dry course, Clement’s LAS tire will be a likely choice for many riders. The LAS, named after the airport code for Las Vegas and in honor of CrossVegas, has a fast, file tread center and shoulder knobs reminiscent of Clement’s other offerings.

Clement describes the design of the LAS:

It’s unique nail-file tread is short and fine at the center of the tire and gets progressively taller and coarser as it approaches the shoulder knobs.

Conventional wisdom in the belt drive arena tells us that belt drive is only for single speed setups, and an internally geared hub or a gearbox is needed to change gear ratios.

Not so according to Trek. Trek is pursing a US patent application that shows a hardtail mountain bike with both belt drive and a rear derailleur. In March of 2012, Trek was issued a US design patent drawn to the chainring for this implementation.

“One or both of the crankset and wheel hub cogs can include more than one cog having different circumferential sizes so as to alter the mechanical advantage provided between the pedals and the driven hub. … It is envisioned that, when provided in a multiple geared format, bicycle 30 be equipped with a front and/or a rear derailleur assembly to facilitate the manual lateral manipulation of the flexible drive member 80 in effectuating shifting of the gearing arrangement of bicycle 30 such that flexible drive member 80 cooperate with one of cogs 120, 200, or 300 as desired.”

In other words, Trek envisions belt-driven bikes to have both front and rear derailleurs.

Here’s a portion of Trek’s belt drive cassette:

In the cross-section of the cassette, you can see that the belt 80 is engaged in the largest cog and moveable to the right as indicated by arrow 434.